Help !. Something simple wrong with this code ?

[Mike2]

Hi, I'm doing a simple calculation which doesn't work with back-testing. If I replace vUpper and vLower with v (in the if ... codes) the code works. The code is as following;

function preMain() {
setPriceStudy(true);
setStudyTitle("Bollinger Bands");
setCursorLabelName("UpperBB", 0 );
setCursorLabelName("MiddleBB", 1 );
setCursorLabelName("LowerBB", 2 );
setDefaultBarFgColor(Color.red, 0); // upper
setDefaultBarFgColor(Color.blue, 1); // middle
setDefaultBarFgColor(Color.green, 2); // lower
setColorPriceBars(true);
setDefaultPriceBarColor(Color.black);
}

var study = new BollingerStudy(10, "Close", 2.0);
var study = new MAStudy(40, 0, "Close", MAStudy.SIMPLE);

function main() {
var v = study.getValue(MAStudy.MA);
if(v == null) return;
var vUpper = study.getValue(BollingerStudy.UPPER);
var vMiddle = study.getValue(BollingerStudy.BASIS);
var vLower = study.getValue(BollingerStudy.LOWER);

// return new Array(vUpper, vMiddle, vLower);

if(close() <= vLower && !Strategy.isLong())
Strategy.doLong("Going Up", Strategy.MARKET, Strategy.THISBAR);

if(close() >= vUpper && !Strategy.isShort())
Strategy.doShort("Going Down", Strategy.MARKET, Strategy.THISBAR);

// if(Strategy.isLong() && high() >= vUpper)
// Strategy.doSell("Sell Up", Strategy.MARKET, Strategy.THISBAR);
// else if(Strategy.isShort() && low() <= vLower && !Stragegy.doSell)
// Strategy.doSell("Sell Down", Strategy.MARKET, Strategy.THISBAR);

if(Strategy.isLong()) setPriceBarColor(Color.lime);
else if(Strategy.isShort()) setPriceBarColor(Color.red);
// return new Array(vUpper, vMiddle, vLower);
return v;
}

[ACM]

Mike2
The problem in the script is that you have assigned the same name to the two studies.
Try the enclosed revision
Alex

function preMain() {
    setPriceStudy(true);
    setStudyTitle("Bollinger Bands");
    setCursorLabelName("UpperBB", 0 );
    setCursorLabelName("MiddleBB", 1 );
    setCursorLabelName("LowerBB", 2 );
    setDefaultBarFgColor(Color.red, 0); // upper
    setDefaultBarFgColor(Color.blue, 1); // middle
    setDefaultBarFgColor(Color.green, 2); // lower
    setColorPriceBars(true);
    setDefaultPriceBarColor(Color.black);
}

var study1 = new BollingerStudy(10, "Close", 2.0);
var study2 = new MAStudy(40, 0, "Close", MAStudy.SIMPLE);

function main() {
    var v = study2.getValue(MAStudy.MA);
    if(v == null) return;
    
    var vUpper = study1.getValue(BollingerStudy.UPPER);
    var vMiddle = study1.getValue(BollingerStudy.BASIS);
    var vLower = study1.getValue(BollingerStudy.LOWER);
        if(vUpper==null||vMiddle==null||vLower==null) return;

    if(close() <= vLower && !Strategy.isLong())
        Strategy.doLong("Going Up", Strategy.MARKET, Strategy.THISBAR);

    if(close() >= vUpper && !Strategy.isShort())
        Strategy.doShort("Going Down", Strategy.MARKET, Strategy.THISBAR); 

    // if(Strategy.isLong() && high() >= vUpper)
        // Strategy.doSell("Sell Up", Strategy.MARKET, Strategy.THISBAR);
    // else if(Strategy.isShort() && low() <= vLower && !Stragegy.doSell)
        // Strategy.doSell("Sell Down", Strategy.MARKET, Strategy.THISBAR);

    if(Strategy.isLong()) setPriceBarColor(Color.lime);
    else if(Strategy.isShort()) setPriceBarColor(Color.red);

    return new Array(vUpper, vMiddle, vLower);
    //return v;
}